Pesticides, such as insecticides, are commonly used in agricultural, industrial, and residential settings to battle destructive, pestiferous, or disease-carrying insects and other animals. Pesticides have achieved significant successes in controlling pestiferous and disease-vector animals, and have increased in their lethality over the years. However, increasingly, the environmental and human health effects of pesticides, as well as their deleterious effects on beneficial insect species and other animals, have caused users to seek other means for controlling pest populations.
Pentatomoidea is a superfamily of insects that includes some of the stink bugs and shield bugs. The name “stink bug” derives from their tendency to eject an odiferous defensive substance when disturbed, typically as a form of anti-predator adaptation. The term “stink bug” is also applied to distantly related species such as Boisea trivittata (Say), the “boxelder bug,” and insects such as beetles in the genus Eleodes such as the pinacate beetle (also known as the stink beetle). Many stink bugs and shield bugs are considered agricultural pest insects, although some are beneficial insects. Examples of both include the spined soldier bug, Podisus maculiventris; several species of Euschistus spp.; the red-shouldered stink bug, Thyanta pallidovirens; the red-banded stink bug, Piezodorus guildinii; the green stink bug, Acrosternum hilare; the kudzu bug (Megacopta cribraria); the conchuela stink bug, Chlorochroa ligata; Uhler's stink bug, C. uhleri; and Say's stink bug, C. sayi. Some insects can generate large populations that damage crop production and are resistant to many pesticides. Moreover, they are immune to genetically modified crops, such as Bt (bacillus thuringiensis) crops. Over the past 5-10 years, stink bugs and plant bugs have become a serious agricultural pest problem in many parts of the world, especially in the regions with large areas of Bt crops.
As an example, the brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), native to Asia, is believed to have been accidentally introduced into the United States as early as 1996, likely as stowaways, possibly as eggs, on packing crates or the like. The BMSB has been recorded in a total of 33 states and the District of Columbia according to information provided by the U.S. Department of Agriculture and the National Agricultural Pest Information System (NAPIS) (http://pest.ceris.purdue.edu). In 2010, the BMSB emerged as a severe pest of fruit and other crops across the region. In addition, this invasive species is a serious nuisance for homeowners and businesses as it overwinters in residential houses, commercial buildings, and warehouses.
The brown marmorated stink bug can cause widespread damage to fruits, vegetables, and field crops, including peaches, apples, green beans, soybeans, corn, tomatoes, cherries, raspberries, and pears. It is a sucking insect that uses its proboscis to pierce the host plant in order to feed. This feeding may cause necrotic areas on the outer surface of fruits, leaf stippling, cat-facing on tree fruits, seed loss, and transmission of plant pathogens. Frequently, the brown marmorated stink bug survives the winter as an adult by entering structures that shield them from the elements. During the overwintering period, stink bugs are generally less active and normally aggregate in dark spaces for hibernation; however, stink bugs may awaken and move (crawl/walk/fly) around in rooms or other indoor spaces when indoor temperatures are high, especially during late winter and early spring. Such indoor activity creates various inconvenient issues (such as unpleasant smells and other annoying activities) for residents.
Aggregation pheromone compounds have been identified from many species of agriculturally important stink bugs. In 2008, Zahn et al. noted that for all phytophagous pentatomoids for which sex or aggregation pheromones have been identified, the compounds were produced by males. J. Chem. Ecol. 34:238 (2008). Males of Thyanta spp., for example, produce methyl (2E,4Z,6Z)-decatrienoate (Millar, Tetrahedron Lett. 38:7971 (1997); McBrien et al., J. Chem. Ecol. 28:1797 (2002)) with or without particular sesquiterpenes (Moraes et al., J. Chem. Ecol. 31:1415 (2005)) that attract a mate. J. G. Millar et al. reported findings regarding male-produced pheromone components of several agriculturally important stink bugs, including T. pallidovirens, A. hilare, C. sayi, C. uhleri, and C. ligata. Bull. Int. Org. of Biol. Control, Pheromone Working Group 25:1 (2002). Methyl (2E,4Z)-decadienoate (M24DD) has been identified as an aggregation pheromone compound or field attractant for seven Euschistus spp. (Aldrich, et al., Environ. Entomol. 20:477 (1991)), and has been used for stink bug monitoring programs in agricultural settings. Another methyl ester, methyl (2E,4E,6Z)-decatrienoate (M246DT), was identified as an aggregation pheromone component of the stink bug Plautia stali Scott (Sugie et al., Appl. Entomol. 31:427 (1996)), and as a field attractant for both adults (males and females) and nymphs of the BMSB, Halyomorpha halys (Stål) and A. hilare (Aldrich et al., J. Chem. Ecol. 33:801 (2007)); Khrimian, Tetrahedron 61:3651 (2005)).
Recently, a sesquiterpene epoxyalcohol, murgantiol (CAS#: 1030630-94-4), was identified by Zahn et al., J. Chem. Ecol. 34:238 (2008), as an aggregation pheromone component of the Harlequin bug, Murgantia histrionica (Hahn), and was recently found by the present inventors as an indoor attractant for BMSBs during their overwintering period indoors (U.S. patent application Ser. No. 13/180,281, filed Jul. 11, 2011). Unfortunately, it is still unknown if the Harlequin bug pheromone, murgantiol, is also attractive to Harlequin stink bugs or BMSBs or other related stink bugs outdoors during the summer mating and feeding season, or whether it is synergistically active as an attractant outdoors with known stink bug attractants, such as M246DT and M24DD for BMSB or Euschistus spp.